JP2001080290A - Writing board surface coat and curable composition for coating surface of writing board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coat for a writing board which makes writing defective when a non-dedicated marking pen is used erroneously for writing, has good dry wiping properties, and is excellent in writing and erasing properties when a dedicated marking pen is used while maintaining high abrasion resistance, durability, and transparency and a curable composition which can form such a coat. SOLUTION: A curable composition comprises a writing board surface coat of at least 90 degree contact angle with water and of 10 degree or below contact angle with ethanol, a polymer (component A), which is suitable for forming the coat, having at least quaternary ammonium salt groups, acryloyl groups, or methacryloyl groups and organopolysiloxane groups bonded to the main chain through nitrogen atoms, and a polyfunctional (meth)acrylate (component B) having at least three in total of acryloyl groups and methacryloyl groups in a molecule. When the total of the component A and the component B is 100 pts.wt., the content of the component A is 1-40 pts.wt. and the content of the component B is 40-99 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface coating of a writing board such as a white board which can be written with a marker pen and has excellent writing and erasing properties, and can be cured by an active energy ray suitable for forming the coating. The present invention relates to a curable composition for a writing board surface coating and a method for forming the cured coating.

[0002]

2. Description of the Related Art Various writing boards (general term for whiteboards, electronic whiteboards, electronic blackboards, etc.) that can be written with a marker pen are now used in a wide range of companies, schools, public facilities, and homes. It is intended to be used instead of the blackboard used. However, since the materials of these writing boards are various, such as enamels, painted boards, resin boards, etc., when written using a marker pen, the erasability may be poor. Therefore, many of these marker pens for writing boards maintain the balance between writing and erasing properties by using an ink to which a release agent (and, in some cases, a wetting agent) is added (for example, Japanese Patent Publication No. Sho 62-4149). Gazette, Japanese Patent Publication No. Hei 6-4805, and JP-A-11-124
No. 529). However, depending on the writing board,
When writing with a special marker pen, too much emphasis is placed on peelability, poor ink adhesion, causing repelling, or conversely, too much emphasis on writability, ink penetrates the board surface, leaving color Or there is a problem that In order to solve such problems, the polarity of the writing surface is controlled (contact angle to water is controlled to 50 to 80 degrees: Japanese Patent Application Laid-Open No. 10-287091), or a hard coat layer is provided on the surface (particularly, Japanese Unexamined Patent Application Publication No. 10-203844, Japanese Unexamined Patent Application Publication No. 11-129688, etc.) have been proposed.

[0003] However, in addition to the above-mentioned problems, the problem of erasure failure (impossibility of wiping or soaking) when erroneously written with a marker other than the dedicated marker pen has become important. A coating for a writing board and a writing board using the same have been developed so that no trace of a line or a trace of a permeation remains. However,
At present, further improvement is required because the ink may not be wiped off by dry wiping with a dry eraser or a tissue, or a color may remain due to ink penetration. In addition, even when the writing board is erroneously written with a pen other than the dedicated marker pen, the writing performance does not decrease so much, and there is a problem that the error is not immediately noticed. Therefore, there is a demand for the development of a writing board with a surface coating that can cause writing defects such as repelling, even if you accidentally try to write with a pen other than the dedicated marker pen, or that can be easily wiped off with dry wiping even if it has been written. It is rare.

However, an acrylic / silicone hard coat agent is applied, a surface-treated polypropylene film or polyethylene film is laminated, or a writing board coated with a melamine resin is further surface-treated. It is difficult to achieve the object by the method on the extension of the conventional technology. On the other hand, various silicone antifouling paints and fluorine antifouling paints have been proposed as having excellent repellency and wiping properties of marker inks, but when these paints are used,
Even with the use of a dedicated marker pen, writing becomes difficult, and the objective has not been sufficiently achieved.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and maintains a high abrasion resistance and durability (high hardness) and transparency (excellent appearance) while maintaining a special marker pen. Provide a surface coating for a writing board that realizes poor writing (repelling) when writing incorrectly with a marker pen other than the above and good dry wiping properties, and also has excellent writing and erasing properties of a dedicated marker pen. It is an object to provide a curable composition capable of forming such a coating.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, when the surface of the writing board has a contact angle in a specific range, the contact angle is limited only to water. It was found that the above-mentioned problems can be solved only when considering ethanol, and that such a surface coating can be obtained by a composition having a specific composition, including a specific polymer. completed. That is, the gist of the present invention is that the contact angle with water is 90
Degrees and a contact angle to ethanol of 10 degrees or less.

[0007] Another aspect of the present invention is to bond to the main chain via at least one of a quaternary ammonium base, an acryloyl group or a methacryloyl group (hereinafter collectively referred to as "(meth) acryloyl group") and a nitrogen atom. (Hereinafter, referred to as “component A”) having a polyorganosiloxane unit and a polyfunctional (meth) acrylate having at least three (meth) acryloyl groups in a molecule (hereinafter, referred to as “component B”). And the total amount of component A and component B is 10
The curable composition capable of forming the above-mentioned writing board surface coating, wherein the content of the component A is 1 to 40 parts by weight and the content of the component B is 60 to 99 parts by weight when 0 parts by weight, the component A
Is a polymer having a structure in which an organopolysiloxane compound having an amino group is added to a (meth) acryloyl group, and the curable composition for a surface coating on a writing board, wherein the component A has a main chain not via a nitrogen atom In the curable composition for a surface coating of a writing board, which is a polymer having an organopolysiloxane unit bonded to the composition.

[0008] Another aspect of the present invention is that 80% by weight of component A
In addition to the above curable composition for a surface coating on a writing board, which is replaced by a polymer having a quaternary ammonium base and a (meth) acryloyl group, component A and component B, With the total amount of the components A and B being 10
In addition to the curable composition for a writing board surface coating containing 35 parts by weight or less per 0 parts by weight, the component A and the component B, an acrylic polymer or a methacrylic polymer is added to the component A.
The curable composition for a writing board surface coating described above containing not more than 30 parts by weight per 100 parts by weight of the total amount of the component B and the curable composition for a writing board surface coating containing a photopolymerization initiator, Exist. Another aspect of the present invention is a method for producing a writing board surface coating, comprising applying the curable composition for writing board surface coating described above, and curing the composition by irradiating with an active energy ray. And a method for producing a film for a writing board surface coating, comprising applying the curable composition for a writing board surface coating on a film substrate and then irradiating the composition with an active energy ray. , There is.

[0009]

Embodiments of the present invention will be described below in detail. First, the contact angle of the surface coating of the present invention will be described, and then the components and composition ratios of the curable composition capable of forming such a coating, and the formation and use of the coating will be described.

(1) Contact Angle The contact angle of water on the surface coating for a writing board of the present invention is 9
It is necessary that the contact angle with respect to ethanol be 0 degree or more and 10 degrees or less. When the contact angle with ethanol exceeds 10 degrees, when a dedicated marker pen for a writing board such as a white board is used, writing performance such as repelling and disturbance of a writing line is reduced. In addition, when the contact angle with water is less than 90 degrees, even when writing with a dedicated marker pen, the wiping property is reduced, or a general oily or aqueous marker pen other than the dedicated marker pen for whiteboard is mistakenly used. However, the stain resistance is reduced, for example, writing becomes possible even when writing is performed by using the method, and the wiping property by dry wiping with a dry eraser for whiteboard or tissue paper is deteriorated. The surface coating having such a specific contact angle can be obtained from a coating formed by irradiating a coating of a composition having a specific component described below with active energy rays. It is important that the components of the composition for forming this coating are selected so that both the hydrophilicity based on quaternary ammonium base and the water repellency based on polysiloxane are present in a good balance on the surface of the obtained coating. It is. In order to exhibit this effect, it is necessary to consider the hydrophilicity / hydrophobicity of the substituents of the monomers constituting the polymer of the component A. Body structure and content, and polyfunctional (meth) of component B
The composition can be selected by trial and error in consideration of the balance between hydrophilicity and water repellency of the whole composition including other components such as acrylate.

(2) Composition for Writing Surface of Writing Board The composition of the present invention capable of forming the surface coating of the writing board having a specific contact angle by curing includes a quaternary ammonium base, a (meth) acryloyl group, Essential components are a polymer having an organopolysiloxane unit bonded to the main chain through a nitrogen atom (component A) and a polyfunctional (meth) acrylate having at least three (meth) acryloyl groups in the molecule (component B). Optionally, a part of component A
A polymer having a quaternary ammonium base and a (meth) acryloyl group, or containing another polymerizable monomer, an acrylic polymer or a methacrylic polymer, and a photopolymerization initiator.

Hereinafter, each of these components will be described.
A quaternary ammonium base, a (meth) acryloyl group, and
Organopolysiloxane bonded to the main chain through a nitrogen atom
(Component A) The polymer (component A) constituting the composition for surface coating of a writing board of the present invention mainly has a stain resistance and, if necessary, an antistatic property to a formed film. It has a quaternary ammonium base, a (meth) acryloyl group, and an organopolysiloxane unit bonded to the main chain via a nitrogen atom. As long as the polymer of the component A has the above-described functional groups and structural units, the structure, the number of the functional groups and the structural units, the bonding position, the molecular weight, the viscosity, and the like are not limited.

In the present specification, "to be bonded to the main chain through a nitrogen atom" means that at least one nitrogen atom is present in the molecular chain connecting the organopolysiloxane unit and the polymer main chain. Means In this specification, acryloyl and methacryloyl are collectively referred to as “(meth) acryloyl”, and acrylate and methacrylate are collectively referred to as “(meth) acrylate”.
And acrylic acid and methacrylic acid are collectively abbreviated as “(meth) acrylic acid”. The polymer of the component A may have an organopolysiloxane unit bonded to the main chain, or may have a structure in which an organopolysiloxane compound having an amino group is added to a (meth) acryloyl group. . The method for producing the polymer of the component A used in the present invention is not particularly limited, but it is preferable to produce the polymer according to the following (Step 1) to (Step 3).

(Step 1) A compound (a1) having one radically polymerizable group and a hydroxyl group in one molecule and a tertiary amine compound (a) having one radically polymerizable group in one molecule
2) and, if necessary, another (meth) copolymerizable therewith.
A polymer having a hydroxyl group is synthesized by polymerizing the acrylate monomer (a3). (Step 2) A compound (a4) having a (meth) acryloyl group and an isocyanate group is added to the polymer produced in the step 1 to synthesize a polymer (a5) having a tertiary amine and a (meth) acryloyl group. I do.

(Step 3) A quaternizing agent is reacted with the polymer obtained in Step 2 to form a quaternary ammonium salt, and then the organopolysiloxane having an amino group at the (meth) acryloyl group in the polymer. Compound (a6) is added. In this step, the quaternization may be performed after the addition of the organopolysiloxane compound (a6). In the case where an organopolysiloxane unit which is bonded to the main chain without using a nitrogen atom is introduced, in step (1), one radical polymerizable group per molecule or two mercapto groups per molecule is used. And then (Step 2) and (Step 3) may be carried out.

The structure of the compound (a1) used in (Step 1) is not particularly limited as long as it is a compound having one radical polymerizable group and a hydroxyl group in one molecule. For example, 2-hydroxyethyl ( (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, 2
-(Meth) acryloyloxyethyl-2-hydroxyethylphthalic acid, and the like. (Step 1)
Is a tertiary amine compound (a2)
The structure is not particularly limited as long as it has two radical polymerizable groups. Preferred is a compound represented by the following general formula (I)
Is a compound having a structure represented by

[0017]

Embedded image

(Wherein, R ₁ is H or CH ₃ , R ₂ and R ₃ are H or an optionally substituted carbon atom 1)
An alkyl group of 1 to 9, k represents an integer of 1 to 6)

As the compound (a2) represented by the above general formula, for example, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) )
Acrylate, N, N-dimethylaminobutyl (meth)
Acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate and the like can be mentioned.

In the copolymerization of the compound (a1) and the compound (a2), in addition to these monomers, the above-mentioned (a)
It is preferable to prepare a multi-component copolymer using a (meth) acrylate monomer (a3) which does not correspond to 1) and (a2). (Meth) used as component (a3)
Specific examples of acrylic acid esters include methyl (meth)
Acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, phenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, Cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate,
(Meth) such as ethoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, butoxyethyl (meth) acrylate, cyanoethyl (meth) acrylate, glycidyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, etc. ) Alkyl or aryl acrylates, polymerizable silane compounds such as trimethoxysilylpropyl (meth) acrylate, triethoxysilylpropyl (meth) acrylate, methyldimethoxysilyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentaful Orpropyl (meth) acrylate, 2- (perfluorohexyl) ethyl (meth) acrylate, 2-
Examples thereof include polymerizable fluoroalkyl esters such as (perfluorooctyl) ethyl (meth) acrylate.

In the (Step 1), the amount of the compound (a1) having one radical polymerizable group and a hydroxyl group in one molecule is 1 to 60% when the total amount of the polymerizable monomer is 100% by weight. % By weight, preferably 5 to 55% by weight. If this amount is less than 1% by weight, the amount of (meth) acryloyl groups and polysiloxane units introduced in the subsequent steps will be small, and the stain resistance tends to be reduced.
On the other hand, when the amount exceeds 60% by weight, the antistatic property tends to be insufficient, and the amount of the compound (a2) is insufficient. The use amount of the tertiary amine compound (a2) is preferably 40 to 99% by weight based on 100% by weight of the copolymerizable monomer,
More preferably, it is 45 to 95% by weight. If it is less than 40% by weight, it becomes difficult to reduce the contact angle with ethanol to the range specified in the present invention.

The polymerization in (Step 1) is generally carried out in a solvent using a radical polymerization initiator. As the solvent, toluene, aromatic hydrocarbons such as xylene, ethyl acetate,
Esters such as propyl acetate and butyl acetate, acetone,
Use ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers such as ethylene glycol dimethyl ether and ethylene glycol diethyl ether; and ether esters such as 2-methoxyethyl acetate, 2-ethoxyethyl acetate and 2-butoxyethyl acetate. These can be used in combination. Examples of the radical polymerization initiator used in the polymerization reaction include organic peroxides such as benzoyl peroxide, di-tert-butyl peroxide and cumene hydroperoxide, and 2,2 ′.
-Azobisisobutyronitrile, 2,2'-azobis-
Azo compounds such as (2,4-dimethylvaleronitrile) and 2,2′-azobis- (4-methoxy-2,4-dimethylvaleronitrile) are preferably used. The monomer concentration in the polymerization reaction solution is usually from 10 to 60% by weight. The polymerization initiator is used in an amount of usually 0.1 to 10% by weight, preferably 0.3 to 2% by weight, based on the monomer mixture.

Next, in (Step 2), a compound (a4) having a (meth) acryloyl group and an isocyanate group is added to the polymer synthesized in (Step 1) to obtain a polymer having a (meth) acryloyl group. (A5) is synthesized. The structure of the compound (a4) used in (Step 2) is not particularly limited as long as it has a (meth) acryloyl group and an isocyanate group. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) A) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid,
(Meth) acrylic acid esters having a hydroxyl group such as pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate, and isocyanate compounds such as tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, and hexamethylene diisocyanate. An adduct by a molar reaction can be mentioned. The compound (a4) having an acryloyl group is preferred because of its high reactivity and rapid curing.

The polymer synthesized in (Step 1) and the compound (a)
4) means a ratio of OH group / NCO group ≧ 1, preferably 1
Used in a ratio of 10 to 10. The reaction is performed at
It is preferable to carry out by stirring for 20 hours. In the reaction of (Step 2), it is preferable to use a polymerization inhibitor such as, for example, hydroquinone, hydroquinone monomethyl ether, catechol, p-tert-butylcatechol, and phenothiazine to prevent polymerization of the (meth) acryloyl group. The amount of the polymerization inhibitor to be used is 0.01 to 1% by weight, preferably 0.05 to 0.5% by weight, based on the reaction mixture. Further, in order to promote the reaction, for example, a catalyst such as dibutyltin dilaurate or 1,4-diazabicyclo [2.2.2] octane may be used.

In (Step 3), the polymer (a5) obtained in (Step 2) is reacted with a quaternizing agent to form a quaternary ammonium salt, and then the organopolysiloxane compound having an amino group (a6 ) Is added to the (meth) acryloyl group, or the polymer (a5) previously synthesized in (Step 2)
After adding the organopolysiloxane compound (a6) having an amino group to the (meth) acryloyl group, a quaternizing agent may be reacted to form a quaternary ammonium salt. Examples of the quaternizing agent used in (Step 3) include alkyl chlorides (eg, methyl chloride, butyl chloride), halides such as methyl bromide, butyl bromide, benzyl chloride, methyl chloroacetate, dimethyl sulfate, diethyl sulfate, and dipropyl sulfate. Examples thereof include alkyl sulfates such as sulfuric acid, and sulfonates such as methyl p-toluenesulfonate, methyl benzenesulfonate, and methyl methanesulfonate.

The reaction for converting a tertiary amine moiety of the polymer (a5) into a quaternary ammonium salt with a quaternizing agent is carried out by using a tertiary amine and a quaternary ammonium salt.
It is preferable to perform the mixing by equimolar mixing of the grading agents and stirring at 20 to 80 ° C. for 1 to 20 hours. In carrying out the quaternization reaction, alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol and isobutanol, 2-methoxyethanol, 2-ethoxyethanol, It is preferable to add ethers such as butoxyethanol, water, or a mixture thereof.

The structure of the organopolysiloxane compound having an amino group used in (Step 3) is not particularly limited as long as it is a compound having at least one organopolysiloxane unit and at least one amino group. The amino group may be bonded to a terminal or a side chain of the organopolysiloxane structure. The organopolysiloxane unit contained in the compound preferably has a structure represented by the following general formula (II).

[0028]

Embedded image

In the formula, R ₄ and R ₅ are a methyl group or a phenyl group, which may be the same or different, and n represents an integer of 5 or more (preferably an integer of 5 to 50). As the organopolysiloxane compound, the amine equivalent is 500 to
A 20,000 polyalkyl (C1-6) aminodialkylsiloxane is preferably used.

In the Michael addition reaction of the organopolysiloxane compound having an amino group to the (meth) acryloyl group of the polymer (a5), the amount used is adjusted so that the ratio of (meth) acryloyl group / amino group becomes 1 or more. Adjust. A more preferred ratio is between 10 and 1000. This reaction is preferably performed with stirring at 60 to 100 ° C. for 1 to 20 hours. By this reaction, a structure in which an organopolysiloxane compound having an amino group is added to a part of the (meth) acryloyl group of the polymer (a5) is formed.

In the polymer used as the component A of the curable composition for a writing board surface coating of the present invention, an organopolysiloxane bonded to the main chain via a nitrogen atom mainly contributes to the development of stain resistance. However, by further introducing a quaternary ammonium base structure, a (meth) acryloyl group structure, and an alkyl group, an aryl group, an aralkyl group, or a fluorine-containing alkyl group structure as necessary, the concentration of the organopolysiloxane unit on the surface is reduced. It is possible to form a controlled surface coating with a specific contact angle to water and alcohol, which is a requirement of the present invention.

Further, by containing an organopolysiloxane unit which binds to the main chain without through a nitrogen atom, the concentration of the organopolysiloxane unit on the surface can be controlled more precisely, so that more preferable water repellency and alcohol-philicity are obtained. May be formed. Such a polymer also having an organopolysiloxane unit bonded to the main chain without via a nitrogen atom includes, in (Step 1), a compound (a1) having one radical polymerizable group and a hydroxyl group in one molecule. Organopolysiloxane having one radically polymerizable group in one molecule or two mercapto groups in one molecule in addition to a tertiary amine compound (a2) having one radically polymerizable group in one molecule The desired polymer can be synthesized by performing (Step 2) and (Step 3) on a polymer obtained by copolymerizing a siloxane compound and, if necessary, another (meth) acrylate. it can.

[0033] Quaternary ammonium base and acryloyl
Having at least one of a methacryloyl group or a methacryloyl group
Up to 80% by weight of the polymer of component A described above may be replaced by a polymer having a quaternary ammonium base and at least one of an acryloyl group or a methacryloyl group. This polymer is blended as necessary in order to control the polarity of the surface of the coating film to be formed and to realize more excellent writability while maintaining stain resistance. As long as this polymer has a (meth) acryloyl group and a quaternary ammonium base, its structure, number and bonding position of each functional group, molecular weight, viscosity and the like are not particularly limited. (Step 5) of the polymer (a5) obtained in (Step 1) and (Step 2), ie, quaternizing with a quaternizing agent to form an ammonium salt Can be obtained by The quaternizing agent and the conditions of the quaternizing reaction that can be used here are the same as those of the component A described above.
Those described in (Step 3) for the production of the polymer can be applied as they are. When the polymer of the component A is replaced with this polymer, the ratio is not more than 80% by weight of the total amount of the component A. When the content of the component A is less than 20% by weight, sufficient stain resistance cannot be exhibited. It is preferable to use a polymer having the same main chain skeleton as the polymer of the component A in view of compatibility.

Polyfunctional (meth) acrylate compound (component
B) The polyfunctional (meth) acrylate (component B) used in the curable composition for a writing board surface coating of the present invention is not particularly limited as long as it has three or more (meth) acryloyl groups in the molecule. The structure and the like are not limited. The polyfunctional (meth) acrylate may have only one of an acryloyl group and a methacryloyl group, or may have both. Those having an acryloyl group are more preferred because of their high reactivity. Examples of the polyfunctional (meth) acrylate having three or more (meth) acryloyl groups in the molecule include trimethylolpropane tri (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, and propylene oxide-modified trimethylol Propane tri (meth) acrylate, tris ((meth) acryloxyethyl) isocyanurate, caprolactone-modified tris ((meth) acryloxyethyl) isocyanurate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, di Pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, alkyl-modified dipen Erythritol tetra (meth) acrylate, alkyl-modified dipentaerythritol penta (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, polyisocyanate and hydroxyl group containing hydroxyl group and three or more (meth) acryloyl groups in the molecule Urethane (meth) obtained by reacting polyfunctional (meth) acrylate
Carboxyl group-containing polyfunctional (meth) acrylates obtained by reacting acrylates, tetracarboxylic dianhydrides and hydroxyl-containing polyfunctional acrylates having a hydroxyl group and three or more (meth) acryloyl groups in the molecule are exemplified. These polyfunctional (meth) acrylates may be used as a mixture of two or more. Specific examples of tetracarboxylic dianhydride include pyromellitic dianhydride, 3, 3 ′,
4,4′-benzophenonetetracarboxylic dianhydride,
3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-diphenylethertetracarboxylic dianhydride, 3,3 ', 4,4'-diphenylsulfonetetracarboxylic Acid dianhydride, 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride, 1,
2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3
-Methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 4- (2,5-dioxotetrahydrofuran-
3-yl) -tetralin-1,2-dicarboxylic anhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2,
3,5,6-tetracarboxylic dianhydride, and the like.

Specific examples of the hydroxyl-containing polyfunctional (meth) acrylate having a hydroxyl group and three or more (meth) acryloyl groups in the molecule include pentaerythritol tri (meth) acrylate and dipentaerythritol tetra (meth) acrylate. Examples include acrylate, dipentaerythritol penta (meth) acrylate, and mixtures thereof. Among these polyfunctional (meth) acrylates having three or more (meth) acryloyl groups in the molecule, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate Carboxyl group-containing polyfunctional (meth) acrylate obtained by reacting acrylate, tetracarboxylic dianhydride with hydroxyl group-containing polyfunctional acrylate having a hydroxyl group and three or more (meth) acryloyl groups in the molecule, etc. It has the effect of improving wear resistance, and is particularly preferred.

Other Polymerizable Monomers In addition to the above components, other curable monomers are formed from the composition of the present invention in the curable composition for a writing board surface coating of the present invention. It can be used as long as the performance of the coating is not impaired. As such other polymerizable monomers,
For example, (meth) acrylate having one or two (meth) acryloyl groups in one molecule, specifically, urethane (meth) acrylate, di (meth) acrylate, epoxy having two (meth) acryloyl groups in one molecule (Meta)
Examples include acrylates and hydroxyl group-containing (meth) acrylates having one (meth) acryloyl group. The amount of such other polymerizable monomer to be used is preferably 35 parts by weight or less when the total amount of the above components A and B is 100 parts by weight.

Other acrylic polymer or methacrylic polymer
The curable composition for a writing board surface coating of the present invention is, in addition to the above-described components, other acrylic polymers or methacrylic polymers as long as the performance of the coating formed from the composition of the present invention is not impaired. Polymers can be added. Examples of such a polymer include polymethyl methacrylate, or a copolymer of an alkyl (meth) acrylate and a (meth) acrylate containing a hydroxyl group, (meth)
Copolymers of acrylic acid alkyl esters with silane coupling agents containing radically polymerizable groups, (meth) acrylic acid ester copolymers having (meth) acryloyl groups in the side chains, and the like can be mentioned. It is not limited. The amount of the acrylic polymer or the methacrylic polymer to be used is the above component A and component B
When the total amount is 100 parts by weight, it is preferable to be 30 parts by weight or less.

Photopolymerization Initiator In curing the curable composition for a writing board surface coating of the present invention, a photopolymerization initiator is used in combination with ultraviolet rays as active energy rays. Examples of such a photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, diethoxyacetophenone, benzyldimethyl ketal, 2-hydroxy-2-methylpropiophenone, and 1-hydroxycyclohexylphenyl. Ketone, benzophenone, 2,4,6-trimethylbenzoindiphenylphosphine oxide, 2-methyl-
[4- (methylthio) phenyl] -2-morpholino-
1-propanone, 2-benzyl-2-dimethylamino-
Examples thereof include 1- (4-morpholinophenyl) -butan-1-one, Michler's ketone, isoamyl N, N-dimethylaminobenzoate, 2-chlorothioxanthone, and 2,4-diethylthioxanthone. These photopolymerization initiators may be used in combination of two or more. Of these, 2-hydroxy-2-methylpropiophenone, 1
Use of an initiator having a hydroxyl group such as -hydroxycyclohexyl phenyl ketone is preferable because the contact angle with respect to ethanol can be further reduced, and the writing property is improved.

Other Ingredients The curable composition for surface coating of a writing board of the present invention may contain an ultraviolet absorber (for example, a benzotriazole-based, benzophenone-based, salicylic acid-based, or cyanoacrylate-based ultraviolet absorber) for the purpose of improving the physical properties of the coating. Agents), antioxidants (eg, hindered phenol, sulfur, phosphorus antioxidants), light stabilizers (eg, hindered amine light stabilizers), antiblocking agents, slip agents, leveling agents and the like. Depending on the purpose, it may be incorporated in the composition in an amount of about 0.01 to 2% by weight. Also,
A solvent may be added to adjust the viscosity of the composition. As this solvent, the same solvent as that used in the production of the polymer is preferable.

(3) Content of each component in the composition As described above, the curable composition for a writing board surface coating of the present invention comprises a quaternary ammonium base, at least one of an acryloyl group or a methacryloyl group, and a nitrogen atom. (Component A) having an organopolysiloxane unit bonded to the main chain via a polymer and a polyfunctional (meth) acrylate having three or more (meth) acryloyl groups in the molecule (Component B)
As an essential component, and if necessary, a part of component A is replaced with a polymer having a quaternary ammonium base and a (meth) acryloyl group, or another polymerizable monomer, an acrylic polymer or a methacrylic It contains a polymer and further contains a photopolymerization initiator and the like. The content of the polymer of the component A in the composition is 1 to 40 parts by weight, preferably 5 to 25 parts by weight, when the total amount of the components A and B is 100 parts by weight. When the content of the component A is less than 1 part by weight,
When the coating has insufficient stain resistance, on the other hand, when it exceeds 40 parts by weight, the abrasion resistance of the coating tends to decrease. Component B
Of the polyfunctional (meth) acrylate (B) having three or more (meth) acryloyl groups in one molecule is 60 parts by weight when the total amount of the components A and B is 100 parts by weight.
-99 parts by weight, preferably 60-95 parts by weight. 6
If the amount is less than 0 parts by weight, the abrasion resistance of the coating is reduced, and if it exceeds 99 parts by weight, the stain resistance tends to be insufficient. Component A,
Other polymerizable monomers other than Component B and other acrylic or methacrylic polymers adjust the viscosity and polarity of the composition, and the resulting coating film has a contact angle with water and ethanol, flexibility, and transparency. It may be used to adjust properties, adhesion, and the like. The total amount of these additives is 35 parts by weight or less, preferably 3 to 20 parts by weight, when the total amount of component A and component B is 100 parts by weight. In addition,
When a photopolymerization initiator is used, the total amount of the polymerizable components, Component A, Component B, and other polymerizable monomers is 10%.
% Or less, preferably 1 to 5% by weight is used in addition to the amounts of the abovementioned components.

(4) Formation and Application of the Film of the Present Invention The film of the present invention is obtained by curing the curable composition containing the above-mentioned components.
For example, it can be formed by coating on a plastic substrate such as polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyamide, vinyl chloride resin, styrene resin, or ABS resin or a film made of these, and curing by irradiating active energy rays. .
A substrate having such a coating on the surface may be used directly as a writing board, and if the coating is formed on the film surface, the film may be attached to the surface of any substrate to form a writing board. Can also. When a coating is directly formed on the surface of a substrate, a melamine resin coated plate, a steel plate, an enamel plate, or the like can be used in addition to the plastic substrate. Examples of a method of applying this composition to a substrate include a dipping method, a flow coating method, a spray coating method, a bar coating method, and a method using a coating device such as a gravure coater, a roll coater, a knife coater, and an air knife coater. it can. The coating thickness is preferably such that the thickness of the coating film after drying and removal of the solvent and irradiation with active energy rays is 1 to 50 μm, preferably 1 to 20 μm. In order to cross-link and cure the applied composition, ultraviolet rays emitted from a light source such as a xenon lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a carbon arc lamp, a tungsten lamp, and a particle accelerator of usually 20 to 2000 kV are used. Generally, a method of irradiating an active energy ray such as an electron beam, α-ray, β-ray, γ-ray or the like taken out of the device.

[0042]

EXAMPLES The present invention will be described more specifically with reference to Synthesis Examples and Examples. Components, ratios, procedures, and the like described in the following Synthesis Examples and Examples depart from the spirit of the present invention. Unless otherwise specified, it can be changed as appropriate. Therefore, the present invention is not limited by the following examples unless it exceeds the gist. Parts and% described in Synthesis Examples and Examples mean parts by weight and% by weight, respectively, unless otherwise specified.

(1) Synthesis Example and Comparative Synthesis Example According to the following synthesis examples, a component having a quaternary ammonium base, at least one of an acryloyl group or a methacryloyl group, and an organopolysiloxane unit bonded to the main chain via a nitrogen atom. A (shown with “A”) and a polymer having at least one of a quaternary ammonium base and an acryloyl or methacryloyl group used to replace a part of component A as necessary (component Collected at the point where quaternization reaction was performed during the production process of A.
(Shown with “X”).

(Synthesis Example 1) 10 parts of 2-hydroxyethyl methacrylate, 2-ethylhexyl methacrylate 3
0 parts, and a solution obtained by mixing a monomer mixture of 60 parts of N, N-dimethylaminoethyl methacrylate and 200 parts of methyl ethyl ketone was heated to 65 ° C. and 2 hours after reaching 65 ° C. , 2,2'-
Azobis (2,4-dimethylvaleronitrile)
Parts were added, and the mixture was further reacted at 65 ° C. for 5 hours, heated to 80 ° C. and reacted for 2 hours to obtain a copolymer having a solid content of 33% (P-1). In addition, isophorone diisocyanate 2
After reacting 2.2 parts with 57.1 parts of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (“Biscoat 300” manufactured by Osaka Organic Chemical Industry Co., Ltd., hydroxyl value 131 mgKOH / g) at 25 ° C. for 3 hours , And 79.3 parts of an adduct obtained by reacting for 5 hours while intermittently raising the temperature to 80 ° C. were added.
The reaction was conducted for a time (in the infrared absorption spectrum, the disappearance of the isocyanate group absorption at 2250 cm ^-1 was confirmed) to obtain a copolymer solution (P-2) having an acryloyl group and having a solid content of 45%. Next, after diluting the obtained copolymer solution with isopropyl alcohol so as to have a solid content of 20%, methyl chloride was introduced and reacted at 50 ° C. for 6 hours to obtain a polymer having a quaternary ammonium base and an acryloyl group. A combined product (X-1) (solid content: 25%) was obtained. Further, an organopolysiloxane compound having an amino group (“TSF47” manufactured by Toshiba Silicon Corporation)
00 ", amine equivalent 3000), 10 parts per 100 parts of solids, react at 80 ° C for 1.5 hours, and bind to the main chain via quaternary ammonium base, acryloyl group and nitrogen atom. A polymer (A-1) having a polymer having a siloxane unit (solid content: 27%) was obtained.

(Synthesis Example 2) The procedure of Synthesis Example 1 was repeated, except that the amount of 2-ethylhexyl methacrylate used was changed from 30 parts to 20 parts and 10 parts of perfluorooctylethyl methacrylate was added. To obtain a copolymer having a solid content of 33% (P-3). This copolymer was reacted with an adduct having an isocyanate group in the same manner as in Synthesis Example 1 to prepare a copolymer solution (P-4) having an acryloyl group and having a solid content of 45%. Subsequently, a quaternization reaction with methyl chloride was performed in the same manner as in Synthesis Example 1 to obtain a polymer (X-2) having a quaternary ammonium base and an acryloyl group (solid content: 25%). Having a polymer having an organopolysiloxane unit bonded to the main chain via a quaternary ammonium base, an acryloyl group and a nitrogen atom by reacting with an organopolysiloxane compound having
2) (solid content 27%) was obtained.

Synthesis Example 3 In Synthesis Example 1, N, N-
The amount of dimethylaminoethyl methacrylate used was changed from 60 parts to 58 parts, and an organopolysiloxane having a methacryloyl group at one end (“FM0” manufactured by Chisso Corporation)
725 ”), except that 2 parts were added, and a polymerization reaction was carried out in the same manner as in Synthesis Example 1 to obtain a copolymer having a solid content of 33% (P-
5). This copolymer is also reacted with an isocyanate group-containing adduct in the same manner as in Synthesis Example 1 to give an acryloyl group-containing copolymer solution having a solid content of 45% (P-6).
Was prepared. Subsequently, a quaternization reaction with methyl chloride was carried out in the same manner as in Synthesis Example 1 to obtain a polymer (X-3) having a quaternary ammonium base and an acryloyl group (solid content 2).
5%), and subsequently reacted with an organopolysiloxane compound having an amino group to obtain a polymer having a polymer having an organopolysiloxane unit bonded to the main chain via a quaternary ammonium base, an acryloyl group and a nitrogen atom. Combined (A-3) (solid content 27%) was obtained.

(Synthesis Example 4) In the same manner as in Synthesis Example 1 except that t-butyl methacrylate was used in place of 2-ethylhexyl methacrylate, a copolymer having a solid content of 33% (P- 7) and an acryloyl group-containing copolymer solution having a solid content of 45% (P-8) prepared by reacting this with an isocyanate group-containing adduct, and further quaternized polymer (X- 4) (solid content 25)
%) And a polymer (A-4) having a polymer having an organopolysiloxane unit bonded to the main chain via a quaternary ammonium base, an acryloyl group and a nitrogen atom (solid content: 27%).

Synthesis Example 5 Synthesis Example 1 was the same as Synthesis Example 1, except that perfluorooctylethyl methacrylate was used instead of 2-ethylhexyl methacrylate.
In the same manner as described above, a copolymer (P-9) having a solid content of 33%, and a copolymer solution having an acryloyl group having a solid content of 45% (P-
10) was prepared, and a quaternized polymer (X)
-5) (solid content 25%) and a polymer (A-5) having a polymer having a quaternary ammonium base, an acryloyl group and an organopolysiloxane unit bonded to the main chain via a nitrogen atom (solid content 28%) ) Got.

(Synthesis Example 6) A copolymer having a solid content of 33% (P-11) was prepared in the same manner as in Synthesis Example 1 except that lauryl methacrylate was used in place of 2-ethylhexyl methacrylate. And a copolymer solution (P-12) having an acryloyl group and having a solid content of 45%, which is obtained by reacting this with an isocyanate group-containing adduct,
Further, the quaternized polymer (X-6) (solid content 2
5%) and a polymer (A-6) having a polymer having an organopolysiloxane unit bonded to the main chain via a quaternary ammonium base, an acryloyl group, and a nitrogen atom (solid content: 28%).

(Comparative Synthesis Example) Methyl methacrylate 60
Parts, trimethoxysilylpropyl methacrylate 10
And an organopolysiloxane having a methacryloyl group at one end (“FM0725”, manufactured by Chisso Corporation) 3
A mixture of 0 parts of the mixture and 200 parts of methyl ethyl ketone was heated and heated to 65 ° C., and two hours after the temperature reached 65 ° C., 2,2′-azobis (2,4-dimethylvalero), respectively. Nitrile) was added in 0.6 parts each, and the mixture was further reacted at 65 ° C. for 5 hours.
After reacting for an hour, a copolymer having a solid content of 33% was obtained.

(2) Examples and Comparative Examples Each component was uniformly mixed in the proportions shown in Table 1 to prepare a curable composition for a writing board surface coating. The curable composition for surface coating of a writing board is coated on a transparent (hazard value: 1.5%) biaxially oriented polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) having a thickness of 100 μm using a bar coater to have a thickness of 3 to 5 μm. Apply so that it becomes 8
After drying by heating at 0 ° C. for 2 minutes, the output density is 115 W / c.
m high-pressure mercury lamp, 700 cm below the light source at a position of 10 cm.
mJ / cm ² UV irradiation, and the coating film
The transparency, abrasion resistance, contact angle, ink stain resistance, fingerprint resistance, and antistatic property were evaluated. Table 2 shows the evaluation results.

(3) Evaluation method The coatings prepared in the examples and comparative examples were evaluated as follows.
Performed by method. Transparency (haze value (%)) It was measured based on JIS K7105.Wear resistance Using a wear wheel of CS-10F manufactured by Caliberase,
Taber abrasion test under a load of 500 g and 100 rotations
And the difference in haze before and after the wear test (試 験 H%)
evaluated.Contact angle Using a P-type contact angle measuring device manufactured by Kyowa Science Co., Ltd., 23 ° C,
Stored in a constant temperature room at 65% relative humidity for 24 hours or more
Use water, ethanol or square
Len was dropped on the surface of the coating to be measured in an amount of 0.002 ml, and 23
It measured at ° C (unit: degree).

Writability to Whiteboard Markers Writability to whiteboard markers was evaluated in terms of repellency, wiping properties, and repeated erasability. In each evaluation, a sample conditioned for 24 hours or more in a constant temperature room at 23 ° C. and a relative humidity of 65% was used, and writing was performed using a whiteboard marker pen (“KOKUYO Whiteboard Marker PM-B102”). (Trade name), manufactured by KOKUYO Co., Ltd., black / red / blue). In addition, this line was wiped with a lined sample at 23.
The test was carried out after standing for at least 24 hours in a constant temperature chamber at 65 ° C. and a relative humidity of 65%. When repetition of the drawing and wiping was repeated, "O" indicates that the repelling was not performed at all from the first time, "△" indicates that the repelling did not occur after the second to fifth drawing, and repelled even after the sixth drawing. Those were marked with "x". The wiping property was tested by wiping the line-drawn sample three times manually using an eraser for whiteboard ("RA-12N" (trade name), manufactured by KOKUYO Corporation). A mark that can be wiped off without leaving any trace of the line was marked with “○”, a trace that was slightly removed was marked with “△”, and a trace that was clearly removed was marked with “×”. Repeated erasability is obtained by repeating the above wiping operation.
Was evaluated by the number of times the condition was maintained. However, in this case, the wiping operation was changed to 10 minutes after the line was drawn.

Ink Stain Resistance The ink stain resistance was evaluated in terms of repellency, wiping properties and repetitive erasability. 23 ° C., relative humidity 6
Use a sample that has been left in a 5% constant temperature room for at least 24 hours to adjust the condition, and write it with an oil-based marker pen ("Magic Ink" (trade name), Teranishi Chemical Industry Co., Ltd., black / red) And by drawing a line with an aqueous marker pen (black). The line was wiped off in a constant temperature chamber at 23 ° C. and a relative humidity of 65%.
Performed after standing for more than an hour. The repelling property is as follows. When the line-wiping is repeated twice, at the time of the third line drawing, the line that repels as the line becomes discontinuous is evaluated as “」 ”, and the line thickness becomes non-uniform or ink is partially missing. “△” indicates that a line can be drawn with a certain width without any problem. The wiping property was tested by wiping the sample three times by hand using a grained paper for wiping (JK Wiper 150-S, manufactured by Jujo Paper Co., Ltd.). The evaluation was performed in three stages. A sample that was completely wiped off by three wipings was evaluated as “O”, a slightly traced line was evaluated as “Δ”, and a sample with some or all of the ink attached was evaluated as “X”. "
The repeated erasability is measured using a lens coating hardness tester (MIL).
(C-675 method, load 0.4 kg weight), if the wipe is done within 5 times, condition adjustment and drawing are performed using the same sample, this test is repeated, and the number of tests until the wipe cannot be repeated is repeatedly erased. Sex value.

In the above evaluations, the repellency and wiping properties were “○” for all the inks, and the repetitive erasability was 10 or more times for the oil-based ink and 5 for the water-based ink.
If the number is more than the number of times, it can be said that the stain resistance is excellent. After immersing the sample having the water-resistant coating in water at normal temperature for 30 minutes, the contact angle and marker ink stain resistance were evaluated and compared with the sample before immersion. A sample with little difference was marked with “○”, and a sample with poor performance was marked with “x”. Fingerprint resistance fingerprint resistance was evaluated by the fingerprint adherence and the fingerprint wiping-off property. Fingerprint adhesion was immediately wiped off with paper (JK Wiper 150
(It is preferable to use a textured paper for wiping such as -S.) The thumb was pressed vertically against the sample surface for 3 seconds, and the adhesion at that time was visually evaluated relative to each other.

As a standard sample, a 0.3% methyl ethyl ketone solution of the polymer prepared in the Comparative Synthesis Example was used and applied to a polyethylene terephthalate film having a thickness of 0.03 μm (the above-mentioned film having a thickness of 100 μm). After curing at 80 ° C for 2 hours, 23 ° C, relative humidity 65
% Was used in a constant temperature room for 24 hours or more.
The evaluation was evaluated as "△" for the same grade as the standard data, "○" for the superior grade, "x" for the inferior grade, and "を" for the one with no fingerprint attached. The fingerprint wiping property was determined by leaving the sample for which the above-mentioned fingerprint adhesion was evaluated for 1 hour, and then applying a textured paper for wiping (JK
Using a wiper 150-S (manufactured by Jujo Paper Co., Ltd.), the number of times of wiping until the fingerprint disappeared when wiped manually was determined. The evaluation was performed in three stages. “O” indicates that the wiping was possible within 3 times, “Δ” indicates that the wiping was possible within 4 to 5 times, and 6
In the case where the erasure could not be performed by wiping the number of times, "x" was given.

[0057] antistatic 23 ° C., using a sample that was allowed to stand for more than 24 hours at 65% relative humidity thermostatic chamber in a surface resistance meter (Takedariken Co.
, TR-8601 type), applied voltage 100V,
It was measured as one minute value.

[0058]

[Table 1]

Note: The amount of component A is a solid content conversion value. (The final solid content concentration was adjusted to 35%.) DPHA = dipentaerythritol hexaacrylate 184 (Irgacure 184) = 1-hydroxycyclohexyl phenyl ketone IPA = isopropyl alcohol

[0060]

[Table 2]

[0061]

[Table 3]

(4) Evaluation of Results Films having a contact angle within the range of the present invention (Examples 1 to 7)
Are excellent in writability with a marker for whiteboard, and excellent in resistance to contamination by other general-purpose marker inks (repellency, wiping property, repetitive erasability), water resistance, antistatic property and the like. On the other hand, from the scope of the present invention, the coatings with a high contact angle to ethanol (Comparative Examples 1 to 4) have significantly higher writability with a whiteboard marker than the coatings within the scope of the present invention. Inferior. Further, from the range of the present invention, the coatings having low contact angles to water (Comparative Examples 5 to 10) have low contact angles to ethanol, but are inferior in resistance to other general-purpose marker ink stains.

[0063]

Industrial Applicability The writing board coating of the present invention has excellent abrasion resistance (high hardness) and transparency (excellent appearance), is excellent in writability with a writing board marker pen, and has a wide variety of types. It has good stain resistance (anti-adhesion properties, removal properties) against dirt and excellent durability, especially writing and wiping properties with a special marker pen, and repellency of other general-purpose marker pens. It is especially excellent in wiping properties.

Continued on the front page (72) Inventor Kazuhide Hayama 1 Tohocho, Yokkaichi-shi, Mie F-term in Yokkaichi Office of Mitsubishi Chemical Corporation (reference) 2C071 CA01 CA02 CD01 4J038 CG142 FA151 FA212 GA01 GA08 KA03 NA05 PA17 PB02 PC02 PC08

Claims (11)

[Claims] 1. A writing board surface coating having a contact angle with water of 90 ° or more and a contact angle with ethanol of 10 ° or less. 2. The method according to claim 1, wherein the film is formed of a film.
4. The writing board surface coating described in 1. 3. An organopolysiloxane unit bonded to the main chain via at least one of a quaternary ammonium base, an acryloyl group or a methacryloyl group (hereinafter collectively referred to as “(meth) acryloyl group”) and a nitrogen atom. (Hereinafter referred to as “Component A”) and a polyfunctional (meth) acrylate having three or more (meth) acryloyl groups in the molecule (hereinafter referred to as “Component B”). The writing board according to claim 1 or 2, wherein the content of the component A is 1 to 40 parts by weight and the content of the component B is 60 to 99 parts by weight, when the total amount with the component B is 100 parts by weight. Curable composition for surface coating. 4. The curable composition for a writing board surface coating according to claim 3, wherein the component A is a polymer having a structure in which an organopolysiloxane compound having an amino group is added to a (meth) acryloyl group. 5. The curable composition for a surface coating on a writing board according to claim 3, wherein the component A is a polymer having an organopolysiloxane unit bonded to the main chain without through a nitrogen atom. 6. The writing board surface coating according to claim 3, wherein 80% by weight or less of the component A is replaced by a polymer having a quaternary ammonium base and a (meth) acryloyl group. Curable composition. 7. The method according to claim 3, wherein in addition to Component A and Component B, other polymerizable monomers are contained in an amount of 35 parts by weight or less per 100 parts by weight of the total amount of Component A and Component B. Item 3. The curable composition for a writing board surface coating according to the item [1]. 8. The method according to claim 3, wherein, in addition to the components A and B, the acrylic polymer or the methacrylic polymer is contained in an amount of 30 parts by weight or less per 100 parts by weight of the total amount of the components A and B. 4. The curable composition for a writing board surface coating according to claim 1. 9. The curable composition for a writing board surface coating according to claim 3, further comprising a photopolymerization initiator. 10. A curable composition for a writing board surface coating according to claim 3, wherein the curable composition is cured by irradiating it with an active energy ray. Manufacturing method of writing board surface coating. 11. A curable composition for surface coating of a writing board according to any one of claims 3 to 9, which is applied on a film substrate, and then the composition is cured by irradiation with active energy rays. A method for producing a film for writing on a surface of a writing board.